title: An SH3 binding motif within the nucleocapsid protein of porcine reproductive and respiratory syndrome virus interacts with the host cellular signaling proteins STAMI, TXK, Fyn, Hck, and cortactin.
abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) causes an economically important global swine disease, and has a complicated virus-host immunomodulation that often leads to a weak Th2 immune response and viral persistence. In this study, we identified a Src homology 3 (SH3) binding motif, PxxPxxP, that is conserved within the N protein of PRRSV strains. Subsequently, we identified five host cellular proteins [signal transducing adaptor molecule (STAM)I, TXK tyrosine kinase (TXK), protein tyrosine kinase fyn (Fyn), hematopoietic cell kinase (Hck), and cortactin] that interact with this SH3 motif. We demonstrated that binding of SH3 proteins with PRRSV N protein depends on at least one intact PxxP motif as disruption of P53 within the motif significantly reduced interaction of each of the 5 proteins. The first PxxP motif appears to be more important for STAMI-N protein interactions whereas the second PxxP motif was more important for Hck interaction. Both STAMI and Hck interactions with PRRSV N protein required an unhindered C-terminal domain as the interaction was only observed with STAMI and Hck proteins with N-terminal but not C-terminal fluorescent tags. We showed that the P56 residue within the SH3 motif is critical for virus lifecycle as mutation resulted in a loss of virus infectivity, however the P50 and P53 mutations did not abolish virus infectivity suggesting that these highly conserved proline residues within the SH3 motif may provide a selective growth advantage through interactions with the host rather than a vital functional element. These results have important implications in understanding PRRSV-host interactions.
authors.affiliation: Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Kenney
authors.affiliation: Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States. Electronic address: xjmeng@vt.edu.
authors.forename: Xiang-Jin
authors.initials: XJ
authors.lastname: Meng
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D051356:Cortactin / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D017930:Genes, Reporter; D000882:Haplorhini; D006801:Humans; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000378:metabolism*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D051572:Proto-Oncogene Proteins c-hck / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013552:Swine; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051356:Cortactin; D019590:Nucleocapsid Proteins; C089848:Tec protein-tyrosine kinase; D011505:Protein-Tyrosine Kinases; D051572:Proto-Oncogene Proteins c-hck
keywords: Fyn; Hck; N protein; Porcine reproductive and respiratory syndrome virus (PRRSV); STAMI; TXK