Identifying Caspases and their Motifs that Cleave Proteins During Influenza A Virus Infection
July 21st, 2022
Influenza A virus (IAV) infection activates the caspases that cleave host and viral proteins, which, in turn, have pro- and antiviral functions. By employing inhibitors, RNA interference, site-directed mutagenesis, and western blotting and RT-qPCR techniques, caspases in infected mammalian cells that cleave host cortactin and histone deacetylases were identified.
Overview
This study investigates the role of caspases in the cleavage of host proteins during Influenza A virus (IAV) infection. By utilizing various molecular techniques, the research identifies specific proteins targeted by caspases in infected mammalian cells.
Key Study Components
Area of Science
- Virology
- Cell Biology
- Molecular Biology
Background
- Influenza A virus (IAV) can activate caspases that cleave both host and viral proteins.
- Caspases play crucial roles in both pro- and antiviral functions.
- Understanding caspase activity can provide insights into viral pathogenesis.
- Identifying cleavage sites may reveal potential therapeutic targets.
Purpose of Study
- To determine if proteins in IAV-infected cells undergo cleavage by caspases.
- To identify specific caspase cleavage sites on host proteins.
- To develop a method applicable to other viral infections and external stimuli.
Methods Used
- Inhibitors and RNA interference to manipulate caspase activity.
- Site-directed mutagenesis to identify cleavage sites.
- Western blotting to detect protein cleavage.
- RT-qPCR for quantifying mRNA levels of target proteins.
Main Results
- Identification of host cortactin and histone deacetylases as cleavage targets.
- Demonstration of caspase activation in IAV-infected cells.
- Confirmation of the method's adaptability for other viruses and stimuli.
- Insights into the dual role of caspases in viral infections.
Conclusions
- Caspases are critical in the cleavage of host proteins during IAV infection.
- The developed method is versatile for studying other infections.
- Understanding caspase activity may lead to new antiviral strategies.
Frequently Asked Questions
Executive Industry Relevance
Dissecting caspase-mediated protein cleavage during Influenza A virus infection enables mechanistic de-risking of host-pathogen interactions and clarifies the functional impact of viral-induced cell death pathways. This workflow supports predictive confidence in target validation by distinguishing direct caspase substrates and their cleavage motifs, informing early-stage antiviral discovery and host response modulation. The approach is broadly adaptable, providing enterprise R&D teams with a reusable strategy for interrogating proteolytic events across diverse infectious and stress-related contexts.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables precise mapping of caspase cleavage sites on host and viral proteins for functional target validation.
- Supports mechanistic de-risking by confirming direct substrate relationships through mutagenesis and biochemical assays.
- Facilitates hypothesis-driven interrogation of cell death pathways relevant to infectious disease models.
Screening & Assay Development
- Establishes validated cellular systems for quantifying caspase-dependent cleavage events via Western blotting.
- Standardizes quantitative readouts for inhibitor and RNAi screening targeting protease activity.
- Enables reproducible assessment of protein stability and resistance to cleavage across engineered mutants.
Translational & Preclinical Research
- Aligns mechanistic findings with disease-relevant models of viral infection and host response.
- Supports continuity from discovery to preclinical validation by enabling cross-species and cross-virus adaptation.
- Provides a platform for evaluating translational biomarkers of caspase activation and substrate cleavage.
Pipeline & Workflow Integration
This method integrates into the discovery-to-preclinical continuum by enabling target validation, mechanistic de-risking, and quantitative assay development for protease-substrate interactions during infection.
- Discovery Biology: Supports hypothesis testing of caspase involvement in protein degradation during viral infection.
- Screening: Delivers quantitative, reproducible outputs for comparing inhibitor, RNAi, and mutagenesis effects on cleavage.
- Analytics: Provides normalized Western blot and RT-qPCR data for robust statistical comparison of experimental conditions.
- Translational Research: Facilitates adaptation to other viruses and stressors, supporting biomarker alignment and disease relevance.
- Enterprise Reuse: Offers a modular, broadly applicable workflow for protease substrate identification across R&D programs.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in target validation and reduces mechanistic ambiguity in host-pathogen studies.
- Operational Value: Promotes standardization, reproducibility, and scalability in protease cleavage assays.
- Strategic Value: Informs go/no-go decisions and enhances capital efficiency by clarifying biological risk early.
- Portfolio Impact: Enables risk-adjusted prioritization and advancement of antiviral and host-modulating candidates.
Implementation Considerations
- Requires foundational molecular and cellular biology expertise for cell culture, transfection, and Western blotting.
- Utilizes standard laboratory instrumentation without need for specialized equipment or software.
- Demands rigorous cross-team standardization of quantitative readouts and normalization protocols.
- Adaptable to various cell lines, viruses, and external stimuli with appropriate controls and validation.
- Necessitates iterative mutagenesis and replication to confirm cleavage motifs and substrate specificity.
Biopharma FAQs
Chapters in this video
0:04
Introduction
0:45
Assessing the Cleavage of Proteins by Caspases in IAV-Infected Cells
2:55
Confirmation of Caspase-Mediated Cleavage of Proteins in IAV-Infected Cells by RNA Interference
4:13
Site-Directed Mutagenesis for Locating the Caspase Cleavage Sites in the Polypeptide
5:49
Results: Role of Caspases in IAV Infection-Induced Degradation of Cortactin
7:32
Conclusion
