Prohibitin mediates the cellular invasion of spring viremia of the carp virus

Spring viremia of carp virus (SVCV) is strongly contagious and pathogenic to common carp and cyprinoid species. However, knowledge of how SVCV enters host cells is still inadequate. In this study, mass spectrometry (MS) was incorporated with tandem affinity purification (TAP) to identify host proteins that interact with SVCV glycoprotein, the main attachment protein of SVCV. Specifically, prohibitin (PHB) received the utmost attention from all the candidate proteins, and its interaction with the SVCV-G protein was confirmed by immunoprecip-itation and immunofluorescence assays. Treatment with PHB-specific inhibitors or knockdown of the expression of PHB by siRNAs resulted in a marked reduction in binding and entry of SVCV on host cells, while over -expression of PHB increased SVCV attachment and invasion. Furthermore, binding of SVCV to ZF4 and FHM cells was inhibited by pre-incubating the virus with recombinant PHB protein (rPHB) or blocking the cell surface PHB with its polyclonal antibodies. In addition, overexpression of PHB on SVCV-nonpermissive Grouper spleen cells (GSs) conferred susceptibility to SVCV infection. In vivo, treatment of rPHB could significantly inhibit SVCV propagation within zebrafish and benefit the survival rate of SVCV-infected zebrafish. These results demonstrate that PHB plays a crucial role in both the attachment and entry stages of SVCV infection.

Automated summary

In this study, mass spectrometry (MS) and tandem affinity purification (TAP) were used to identify host proteins that interact with the glycoprotein of Spring viremia of carp virus (SVCV). Prohibitin (PHB) was found to have the strongest interaction with SVCV-G protein. Further experiments confirmed that PHB is essential for the binding and entry of SVCV into host cells. Overexpression of PHB increased SVCV attachment, while inhibition of PHB expression reduced binding and entry of SVCV. Treatment with recombinant PHB protein (rPHB) or blocking cell surface PHB inhibited SVCV binding to host cells. In vivo studies showed that treatment with rPHB significantly inhibited SVCV propagation and improved the survival rate of infected zebrafish.