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In Vitro ELISA Test to Evaluate Rabies Vaccine Potency
Published on: May 11, 2020
Quantitative Analysis of the Microtubule Interaction of Rabies Virus P3 Protein: Roles in Immune Evasion and
Aaron Brice1, Donna R Whelan2, Naoto Ito3,4
1Viral Pathogenesis Laboratory, Department of Biochemistry and Molecular Biology, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia.
Abstract:
Although microtubules (MTs) are known to have important roles in intracellular transport of many viruses, a number of reports suggest that specific viral MT-associated proteins (MAPs) target MTs to subvert distinct MT-dependent cellular processes. The precise functional importance of these interactions and their roles in pathogenesis, however, remain largely unresolved. To assess the association with disease of the rabies virus (RABV) MAP, P3, we quantitatively compared the phenotypes of P3 from a pathogenic RABV strain, Nishigahara (Ni) and a non-pathogenic Ni-derivative strain, Ni-CE. Using confocal/live-cell imaging and dSTORM super-resolution microscopy to quantify protein interactions with the MT network and with individual MT filaments, we found that the interaction by Ni-CE-P3 is significantly impaired compared with Ni-P3. This correlated with an impaired capacity to effect association of the transcription factor STAT1 with MTs and to antagonize interferon (IFN)/STAT1-dependent antiviral signaling. Importantly, we identified a single mutation in Ni-CE-P3 that is sufficient to inhibit MT-association and IFN-antagonist function of Ni-P3, and showed that this mutation alone attenuates the pathogenicity of RABV. These data provide evidence that the viral protein-MT interface has important roles in pathogenesis, suggesting that this interface could provide targets for vaccine/antiviral drug development.
Insights
Rabies virus (RABV) P3 protein interactions with microtubules are crucial for pathogenicity. A single mutation impairs microtubule binding, reducing viral disease potential and interferon antagonism.
Area of Science:
- Virology and Cell Biology
- Microbiology and Infectious Diseases
Background:
- Microtubules (MTs) are vital for intracellular transport, and viruses often hijack them.
- Viral proteins can manipulate MTs to subvert cellular processes, but their role in pathogenesis is unclear.
- The rabies virus (RABV) P3 protein is a potential MT-associated protein (MAP) involved in viral pathogenesis.
Purpose of the Study:
- To investigate the role of the RABV P3 protein's interaction with microtubules in viral pathogenesis.
- To determine if specific P3 protein-microtubule interactions are essential for disease development.
Main Methods:
- Quantitative comparison of P3 protein phenotypes from pathogenic (Nishigahara) and non-pathogenic (Ni-CE) RABV strains.
- Confocal/live-cell imaging and super-resolution microscopy (dSTORM) to analyze protein-MT interactions.
- Assessment of STAT1 association with MTs and interferon (IFN)/STAT1-dependent antiviral signaling.
Main Results:
- The P3 protein from the non-pathogenic Ni-CE strain showed significantly impaired interaction with MTs compared to the pathogenic strain.
- This impaired MT interaction correlated with a reduced ability to associate STAT1 with MTs and antagonize IFN/STAT1 signaling.
- A single mutation in Ni-CE-P3 was identified that inhibits MT-association and IFN-antagonist function, and this mutation alone attenuated RABV pathogenicity.
Conclusions:
- The interaction between viral proteins, specifically RABV P3, and microtubules is critical for viral pathogenesis.
- The viral protein-MT interface represents a potential target for developing novel antiviral therapies and vaccines.
- Understanding these molecular interactions can elucidate mechanisms of viral disease and host immune evasion.
