Interactomic landscape of PA-X-chicken protein complexes of H5N1 influenza A virus.

UNLABELLED

As a newly identified isoform generated from the PA segment and an essential factor for viral virulence, little is known about PA-X-host interactions. Here we present the interactomic landscape of PA-X protein of H5N1 influenza A virus (IAV), described using data generated from affinity purification and mass spectrometry (AP-MS). PA-X was exogenously expressed in chicken fibroblast cells and PA-X associated protein complexes were identified by AP-MS. Using a high confidence threshold for interaction 56 unique proteins were found to have physical interactions with PA-X. PA-X associated host factors showed strong enrichment for specific protein domains, including annexin and WD40 domains. Many proteins that have been described as pro or antiviral host proteins interact with PA-X, indicating the possible effect of these proteins on influenza A viral infections facilitated by interactions with PA-X. This study has uncovered the comprehensive interactomic landscape of PA-X and laid the foundation for further understanding of PA-X function in terms of viral-host protein interactions.

BIOLOGICAL SIGNIFICANCE

Identification of viral-host interacting proteins is vital for the comprehensive understanding of how virus recruits the host cellular machinery and how host antagonizes virus infection. Our study reveals the viral-host interactome of PA-X and uncovers interactions between host proteins and PA-X which might have crucial roles in viral infection.