Orf Virus 002 Protein Targets Ovine Protein S100A4 and Inhibits NF-κB Signaling

Abstract

Orf virus (ORFV), a member of Parapoxvirus, has evolved various strategies to modulate the immune responses of host cells. The ORFV-encoded protein ORFV002, a regulator factor, has been found to inhibit the acetylation of NF-κB-p65 by blocking phosphorylation of NF-κB-p65 at Ser276 and also to disrupt the binding of NF-κB-p65 and p300. To explore the mechanism by which ORFV002 regulates NF-κB signaling, the understanding of ORFV002 potential binding partners in host cells is critical. In this study, ovine S100 calcium binding protein A4 (S100A4), prolyl endopeptidase-like (PREPL) and NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 8 (NDUFA8) were found to interact with ORFV002 based on the yeast two-hybrid (Y2H) assay using a cDNA library derived from primary ovine fetal turbinate cells (OFTu). GST pull-down and bidirectional co-immunoprecipitation assay results demonstrate that ORFV002 interacts with S100A4 directly. Following the pEGFP-ORFV002 (p002GFP) transfection, we found that cytoplasmic S100A4 translocates into the nucleus and co-localizes with ORFV002. Furthermore, the inhibitory effect of ORFV002 on NF-κB signaling was significantly restored by S100A4 knock-down phenotype, suggesting that ovine S100A4 participates in the ORFV002-mediated NF-κB signaling. These data demonstrate that ORFV002 inhibits the NF-κB activation through its interaction with S100A4 along with its nucleus translocation.

Orf Virus: A New Class of Immunotherapy Drugs

“…The regulation of NF-κB includes the regulation of IκB in the cytoplasm, and posttranslational phosphorylation, acetylation, and methylation in the nucleus. The ORFV 002, 024, 073, 119, and 121 genes have been reported that play roles in NF-κB pathway regulation [32][33][34][35][36][37][38].…”

“…ORFV002-encoded protein can inhibit the activation of NF-κB pathway induced by TNF-α and ORFV virus infection, which may through interfering the interaction between NF-κB-p65 and P300 in the nucleus block the acetylation of NF-κB-p65 Lys310 when phosphorylation occurs at ORFV002 Ser 276 [32,33]. The 52 amino acids of ORFV002 N terminal may interact with protein S100A4 [34].…”

Orf virus: A promising new therapeutic agent

“…ORFV genes have been reported to play roles in NF-κB pathway regulation. [62][63][64][65][66][67][68] The ORFV002 gene, located in the nucleus, encodes a protein inhibiting activation of the NF-κB pathway by TNF-α and ORFV infection. ORFV002 may interfere with the interaction between NF-κB-p65 and P300 in the nucleus, thereby blocking the acetylation of NF-κB-p65 Lys310 when ORFV002 Ser276 is phosphorylated.…”

“…62,63 Additional studies have shown that ORFV002 inhibits NF-κB activation through interacting with the S100 calcium binding protein A4 (S100A4). 64 Recent studies have found that the ORFV024 protein blocks the NF-κB signaling pathway by combining with LAGE3 to inhibit the phosphorylation of inhibitor of nuclear factor kappa-B kinase (IKK) complex. ORFV024 affects the phosphorylation of NF-κB-p65, inhibiting the secretion of important cytokines and regulating the host immune response, 65 suggesting that ORFV024 is a virulence determinant for ORFV in the natural host.…”

Integrated Analysis of Differentially Expressed miRNAs and mRNAs in Goat Skin Fibroblast Cells in Response to Orf Virus Infection Reveals That cfa-let-7a Regulates Thrombospondin 1 Expression

“…Initially, primary lamb testis and primary lamb kidney cells were commonly used for ORFV isolation [6]. Primary fetal lamb muscle cells [7], ovine fetal turbinate cells [8], and goat skin fibroblast cells [9] have also been widely used for ORFV isolation. Madin-Darby bovine and Madin-Darby ovine kidney are the most commonly used cell lines for ORFV isolation and propagation [10].…”