Characterization of the interactome of the porcine reproductive and respiratory syndrome virus (PRRSV) NSP2 protein reveals the hyper variable region as a binding platform for association with 14-3-3 proteins

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major threat to the swine industry worldwide and hence global food security, exacerbated by a newly emerged highly pathogenic (HP-PRRSV) strain from China. PRRSV non-structural protein 2 (nsp2) is a multifunctional polypeptide with strain-dependent influences on pathogenicity. A number of discrete functional regions have been identified on the protein. Quantitative label free proteomics was used to identify cellular binding partners of nsp2 expressed by HP-PRRSV. This allowed the identification of potential cellular interacting partners and the discrimination of non-specific interactions. The interactome data was further investigated and validated using biological replicates and also compared with nsp2 from a low pathogenic (LP) strain of PRRSV. Validation included both forward and reverse pulldowns and confocal microscopy. The data indicated that nsp2 interacted with a number of cellular proteins including; 14-3-3, CD2AP and other components of cellular aggresomes. The hyper variable region of nsp2 protein was identified as a binding platform for association with 14-3-3 proteins.