ATP Hydrolysis Enhances RNA Recognition and Antiviral Signal Transduction by the Innate Immune Sensor, Laboratory of Genetics and Physiology 2 (LGP2)

Bruns, Annie M.; Pollpeter, Darja; Hadizadeh, Nastaran; Myong, Sua; Marko, John F.; Horvath, Curt M.

doi:10.1074/jbc.m112.424416

Cited by 83 publications

(150 citation statements)

References 27 publications

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“…This notion is supported by the characterization of an EMCV-derived MDA5 agonist RNA that was identified not on the basis of interaction with MDA5 but through its association with LGP2 (21). Replacing LGP2 with the enzymatically inactive K30A mutant by knock-in does not reconstitute defective positive signaling responses, indicating the importance of ATP hydrolysis in LGP2-positive regulation (19), but this same LGP2 mutant retains negative regulatory functions (14,22). Biochemical analysis and single-molecule RNA binding studies demonstrate that LGP2 uses ATP hydrolysis to enhance its ability to associate with diverse dsRNA species, enabling it to act in concert with MDA5 to maximize antiviral signal transduction (22,23).…”

supporting

confidence: 48%

“…LGP2 mutants that target helicase motif I (MI; K30A; defective for ATP hydrolysis but able to bind RNA [10]) or motif III (MIII; T167A S169A; defective for both ATP hydrolysis and RNA binding [10]) served as negative controls. These mutants fail to augment MDA5 signaling but retain negative regulation (22) (Fig. 1D).…”

Section: Generation Of a Biologically Activementioning

confidence: 99%

“…We previously used a similar functional assay to demonstrate that LGP2 ATP hydrolysis and RNA recognition are required to synergistically enhance MDA5-mediated signaling (22). Expression of MDA5 activates IFN-␤-luciferase regardless of poly(I·C) stimulation (7,12,22), and MDA5 signaling can be further enhanced by titration of LGP2. Increasing the amount of LGP2 expression by transfection with more plasmid DNA ultimately results in suppression of reporter gene activity.…”

Section: Generation Of a Biologically Activementioning

confidence: 99%

“…Replacing LGP2 with the enzymatically inactive K30A mutant by knock-in does not reconstitute defective positive signaling responses, indicating the importance of ATP hydrolysis in LGP2-positive regulation (19), but this same LGP2 mutant retains negative regulatory functions (14,22). Biochemical analysis and single-molecule RNA binding studies demonstrate that LGP2 uses ATP hydrolysis to enhance its ability to associate with diverse dsRNA species, enabling it to act in concert with MDA5 to maximize antiviral signal transduction (22,23). These results indicate an ATP-dependent function of LGP2 in promoting signal transduction in response to intracellular virus infections.…”

mentioning

confidence: 99%

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Paramyxovirus V Protein Interaction with the Antiviral Sensor LGP2 Disrupts MDA5 Signaling Enhancement but Is Not Relevant to LGP2-Mediated RLR Signaling Inhibition

Rodriguez

Horvath

2014

J Virol

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The interferon antiviral system is a primary barrier to virus replication triggered upon recognition of nonself RNAs by the cytoplasmic sensors encoded by retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated gene 5 (MDA5), and laboratory of genetics and physiology gene 2 (LGP2). Paramyxovirus V proteins are interferon antagonists that can selectively interact with MDA5 and LGP2 through contact with a discrete helicase domain region. Interaction with MDA5, an activator of antiviral signaling, disrupts interferon gene expression and antiviral responses. LGP2 has more diverse reported roles as both a coactivator of MDA5 and a negative regulator of both RIG-I and MDA5. This functional dichotomy, along with the concurrent interference with both cellular targets, has made it difficult to assess the unique consequences of V protein interaction with LGP2. To directly evaluate the impact of LGP2 interference, MDA5 and LGP2 variants unable to be recognized by measles virus and parainfluenza virus 5 (PIV5) V proteins were tested in signaling assays. Results indicate that interaction with LGP2 specifically prevents coactivation of MDA5 signaling and that LGP2's negative regulatory capacity was not affected. V proteins only partially antagonize RIG-I at high concentrations, and their expression had no additive effects on LGP2-mediated negative regulation. However, conversion of RIG-I to a direct V protein target was accomplished by only two amino acid substitutions that allowed both V protein interaction and efficient interference. These results clarify the unique consequences of MDA5 and LGP2 interference by paramyxovirus V proteins and help resolve the distinct roles of LGP2 in both activation and inhibition of antiviral signal transduction. IMPORTANCE Paramyxovirus V proteins interact with two innate immune receptors, MDA5 andLGP2, but not RIG-I. V proteins prevent MDA5 from signaling to the beta interferon promoter, but the consequences of LGP2 targeting are poorly understood. As the V protein targets MDA5 and LGP2 simultaneously, and LGP2 is both a positive and negative regulator of both MDA5 and RIG-I, it has been difficult to evaluate the specific advantages conferred by LGP2 targeting. Experiments with V-insensitive proteins revealed that the primary outcome of LGP2 interference is suppression of its ability to synergize with MDA5. LGP2's negative regulation of MDA5 and RIG-I remains intact irrespective of V protein interaction. Complementary experiments demonstrate that RIG-I can be converted to V protein sensitivity by two amino acid substitutions. These findings clarify the functions of LGP2 as a positive regulator of MDA5 signaling, demonstrate the basis for V-mediated LGP2 targeting, and broaden our understanding of paramyxovirus-host interactions.

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supporting

confidence: 48%

Section: Generation Of a Biologically Activementioning

confidence: 99%

Section: Generation Of a Biologically Activementioning

confidence: 99%

mentioning

confidence: 99%

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Paramyxovirus V Protein Interaction with the Antiviral Sensor LGP2 Disrupts MDA5 Signaling Enhancement but Is Not Relevant to LGP2-Mediated RLR Signaling Inhibition

Rodriguez

Horvath

2014

J Virol

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“…However, recently, Bruns et al demonstrated that robust basal ATPase activity allows LGP2 to diversify its RNA recognition capacity. 58 This result is interesting in light of the fact that both RIG-I and MDA5 completely lack basal ATPase activity. Moreover, the duck apo RIG-I structure suggests that ATP binding and hydrolysis can only occur in the presence of RNA.…”

Section: 5152mentioning

confidence: 78%

Toward a crystal-clear view of the viral RNA sensing and response by RIG-I-like receptors

Luo

2014

RNA Biology

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Negative regulators of the RIG‐I‐like receptor signaling pathway

2017

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SUMMARY Upon recognition of specific molecular patterns on viruses, bacteria and fungi, host cells trigger an innate immune response, which culminates in the production of type I interferons (IFN), pro-inflammatory cytokines and chemokines, and restricts pathogen replication and spread within the host. At each stage of the immune response, there are stimulatory and inhibitory signals that regulate the magnitude, quality, and character of the response. Positive regulation promotes an antiviral state to control and eventually clear infection whereas negative regulation dampens inflammation and prevents immune-mediated tissue damage. An over-exuberant innate immune response can lead to the destruction of cells and tissues, and the development of spontaneous autoimmunity. The RIG-I-like receptors (RLRs) retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) belong to a family of cytosolic host RNA helicases that recognize distinct non-self RNA signatures and trigger innate immune responses against several RNA virus infections. The RLR signaling pathway is tightly regulated to achieve a well-orchestrated response aimed at maximizing antiviral immunity and minimizing immune-mediated pathology. This review highlights contemporary findings on negative regulators of the RLR signaling pathway, with specific focus on the proteins and biological processes that directly regulate RIG-I, MDA5 and MAVS function.

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ATP Hydrolysis Enhances RNA Recognition and Antiviral Signal Transduction by the Innate Immune Sensor, Laboratory of Genetics and Physiology 2 (LGP2)

Cited by 83 publications

References 27 publications

Paramyxovirus V Protein Interaction with the Antiviral Sensor LGP2 Disrupts MDA5 Signaling Enhancement but Is Not Relevant to LGP2-Mediated RLR Signaling Inhibition

Paramyxovirus V Protein Interaction with the Antiviral Sensor LGP2 Disrupts MDA5 Signaling Enhancement but Is Not Relevant to LGP2-Mediated RLR Signaling Inhibition

Toward a crystal-clear view of the viral RNA sensing and response by RIG-I-like receptors

Negative regulators of the RIG‐I‐like receptor signaling pathway

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