Proteomic characterization of a novel structural protein ORF5a of porcine reproductive and respiratory syndrome virus

► The PRRSV ORF5a protein exists as non-covalently linked oligomers. ► ORF5a expression has no effect on cell growth. ► Four cellular proteins involved in cytoskeleton networks were altered by ORF5a. ► Two hnRNPs family members (A1 and K) were changed in ORF5a-expressing PAM cells.