Virologica Sinica

, Volume 31, Issue 6, pp 480–489 | Cite as

The role of viral protein Ac34 in nuclear relocation of subunits of the actin-related protein 2/3 complex

Research article


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.


Autographa californica multiple nucleopolyhedrovirus (AcMNPV) Ac34 Arp2/3 complex nuclear relocation 


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We thank Dr. Jan van Lent of Wageningen University and Dr. Ding Gao of core facilities in Wuhan Institute of Virology, CAS, for their technical assistance with fluorescence microscopy. This work was supported by grants from National Natural Science Foundation of China (31030027, 31470261, 31321001, and 31270191). The Royal Dutch Academy of Science and Arts (08-PSABD-01) is acknowledged for financing part of this research.

Supplementary material

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The role of viral protein Ac34 in nuclear relocation of subunits of the actin-related protein 2/3 complex


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Copyright information

© Wuhan Institute of Virology, CAS and Springer Science+Business Media Singapore 2016

Authors and Affiliations

  1. 1.State Key Laboratory of Virology, Wuhan Institute of VirologyChinese Academy of SciencesWuhanChina
  2. 2.University of Chinese Academy of SciencesBeijingChina

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