Viral pathogens frequently hijack the host actin polymerization machinery to facilitate their infection. Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) is one of the unique insect virus that inducing actin polymerization occurring in the nucleus, which requires relocation of cytoplasmic actin polymerization machinery, including actin-related protein 2/3 complex (Arp2/3), to the nucleus. Therefore, the alphabaculovirus-infection system could serve as a research model for investigating the nuclear import mechanism of Arp2/3. In this issue, Wang et al. investigated the spatial changes of Arp2/3 subunits induced by the viral replication-associated protein Ac34 in Sf9 cells. The cover shows the relocation of Arp2/3 subunits (P40, Arp2, P34, P21, and P20) in the presence of the viral late gene product Ac34. See page 472-479 for details.
IKKε作为一种非经典的IκB激酶，在天然免疫中被广泛研究。最近的研究发现IKKε在干扰素信号通路中发挥重要作用。同时， 最新的研究发现IKKε在获得性免疫中也具有重要的功能。IKKε负调控CD8 T 细胞激活，暗示IKKε可能是一个潜在的免疫治疗的靶点，可以通过抑制IKKε来提高抗病毒和抗肿瘤T细胞免疫。我们概述了IKKε在干扰素信号通路及T细胞免疫中的研究进展，同时提出了亟待解决的相关学术问题。
The actin nucleator actin-related protein complex (Arp2/3) is composed of seven subunits: Arp2,Arp3, p40/ARPC1 (P40), p34/ARPC2 (P34), p21/ARPC3 (P21), p20/ARPC4 (P20), and p16/ARPC5(P16). Arp2/3 plays crucial roles in a variety of cellular activities through regulation of actin polymerization. Autographa californica multiple nucleopolyhedrovirus (AcMNPV), one of the beststudied alphabaculoviruses, induces Arp2/3 nuclear relocation and mediates nuclear actin polymerization to assist in virus replication. We have demonstrated that Ac34, a viral late-gene product, induces translocation of the P40 subunit of Arp2/3 to the nucleus during AcMNPV infection. However, it remains unknown whether Ac34 could relocate other Arp2/3 subunits to the nucleus. In this study, the effects of the viral protein Ac34 on the distribution of these subunits were studied by an immunofluorescence assay. Arp2, P34, P21, and P20 cloned from Spodoptera frugiperda (Sf9) cells showed mainly cytoplasmic localization and were relocated to the nucleus in the presence of Ac34. In addition, Arp3 was localized in the cytoplasm in both the presence and absence of Ac34, and P16 showed whole-cell localization. In contrast to Sf9 cells, all subunits of mammalian Arp2/3 showed no nuclear relocation in the presence of Ac34. Co-immunoprecipitation analysis of the interaction between Ac34 and Arp2/3 subunits revealed that Ac34 bound to P40, P34, and P20 of Sf9 cells. However, none of the subunits of mammalian Arp2/3 interacted with Ac34, indicating that protein-protein interaction is essential for Ac34 to relocate Arp2/3 subunits to the nucleus.
The envelope fusion protein F of baculoviruses is a class I viral fusion protein which play a significant role during virus entry into insect cells. F is initially synthesized as a precursor (F0) and then cleaved into a disulfide-linked F1 and F2 subunits during the process of protein maturation and secretion. To facilitate further investigation into the structure and function of F protein during virus infection, monoclonal antibodies (mAbs) against the F2 subunit of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) (HaF) were generated. Two kinds of mAbs were obtained according to their different recognition epitopes: one kind of mAbs, as represented by 38F10, recognizes amino acid (aa) 85 to 123 of F2 and the other kind, represented by 44D11, recognizes aa 148 to 173 of F2. Western blot and immunofluorescence assay confirmed that both of the mAbs recognized the F protein expressed in HearNPV infected cells, however, only 44D11 could neutralize HearNPV infection. The results further showed that 44D11 may not interact with a receptor binding epitope, rather it was demonstrated to inhibit syncytium formation in cells expressing the HaF protein. The results imply that the monoclonal antibody 44D11 recognizes a region within HaF2 that may be involved in the F-mediated membrane fusion process.
On July 2, 2015, four pigs with severe respiratory distress and high fever (>40.0 ℃) at a farm in Jeonpook province in the Southern region of South Korea were euthanized, and their lung tissues were collected and homogenized in PBS. The homogenized samples were inoculated into the wells of 6-well plates containing MadinDarby Canine Kidney (MDCK) cells in MEM with 1 μg/mL trypsin. One influenza A virus, A/Swine/Korea/S2001/2015 (H3N2), was isolated from one sample.