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Monitoring Activation of the Antiviral Pattern Recognition Receptors RIG-I And PKR By Limited Protease Digestion and Native PAGE
Published on: July 29, 2014
Master sensors of pathogenic RNA - RIG-I like receptors
1Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, 53105 Bonn, Germany.
Abstract:
Initiating the immune response to invading pathogens, the innate immune system is constituted of immune receptors (pattern recognition receptors, PRR) that sense microbe-associated molecular patterns (MAMPs). Detection of pathogens triggers intracellular defense mechanisms, such as the secretion of cytokines or chemokines to alarm neighboring cells and attract or activate immune cells. The innate immune response to viruses is mostly based on PRRs that detect the unusual structure, modification or location of viral nucleic acids. Most of the highly pathogenic and emerging viruses are RNA genome-based viruses, which can give rise to zoonotic and epidemic diseases or cause viral hemorrhagic fever. As viral RNA is located in the same compartment as host RNA, PRRs in the cytosol have to discriminate between viral and endogenous RNA by virtue of their structure or modification. This challenging task is taken on by the homologous cytosolic DExD/H-box family helicases RIG-I and MDA5, which control the innate immune response to most RNA viruses. This review focuses on the molecular basis for RIG-I like receptor (RLR) activation by synthetic and natural ligands and will discuss controversial ligand definitions.
Insights
The innate immune system uses pattern recognition receptors (PRRs) to detect viral RNA. RIG-I-like receptors (RLRs) are crucial for distinguishing viral RNA from host RNA, initiating antiviral defenses.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- The innate immune system protects against pathogens using pattern recognition receptors (PRRs) that identify microbe-associated molecular patterns (MAMPs).
- Viral RNA detection by PRRs is critical for initiating intracellular defense mechanisms against RNA viruses.
- RIG-I-like receptors (RLRs), including RIG-I and MDA5, are key cytosolic sensors that discriminate between viral and host RNA.
Purpose of the Study:
- To review the molecular mechanisms of RIG-I-like receptor (RLR) activation.
- To discuss the activation of RLRs by both synthetic and natural ligands.
- To explore controversial definitions of RLR ligands.
Main Methods:
- Literature review focusing on molecular mechanisms of RLR activation.
- Analysis of studies on viral RNA recognition by PRRs.
- Discussion of ligand-binding properties and activation pathways of RIG-I and MDA5.
Main Results:
- RLRs distinguish viral RNA from host RNA based on structural and modification patterns.
- RIG-I and MDA5 are homologous cytosolic DExD/H-box helicases essential for antiviral innate immunity.
- Ligand recognition by RLRs involves specific structural features of viral RNA.
Conclusions:
- RLRs play a pivotal role in the innate immune response to RNA viruses.
- Understanding RLR activation is crucial for developing antiviral therapies.
- Further research is needed to clarify controversial aspects of RLR ligand definition.
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