Identification of human hepatocyte protein(s), which binds specifically to the recombinant envelope-2/non-structural-1 protein of hepatitis C virus

NM23 Is a CP-Binding Protein Involved in Infectious Hypodermal and Hematopoietic Necrosis Virus Infection in Shrimp

Simple Summary

In this study, we aimed to identify the putative host cell receptor for Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) CP(Capsid Protein) in the gill membrane of LitoPenaeus vannamei. We established that NM23 is a host cell binding partner for IHHNV CP. Our study is probably the first to address the host cell IHHNV receptor and could provide novel insights into the pathogenesis of IHHNV. We feel that this paper is of interest to the readers of Animals.

Abstract

The aim of this study was to identify the putative host cell receptor for Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) CP in the gill membrane of L. vannamei. Putative CP binding partners were screened first using a 2-dimensional Virus Overlay Protein Blot Assay (VOPBA) to probe isolated gill membrane proteins using recombinant CP. Putative binding partners were identified using mass spectrometry. A Phage Display Random Dodecapeptide Library was used to screen for dodecapeptides and motifs that bound to CP. Finally, putative binding pairs were confirmed using GST(glutathione-S-transferase) pulldown assays. 2-Dimensional VOPBA identified NM23 as a putative binding partner for IHHNV CP. GST pulldown experiments confirmed the direct interaction of NM23 and IHHNV CP. The phage display library was used to identify six groups of dodecapeptides that bound to CP. From these peptides, three characteristic binding motifs were identified, SW*Y, SKWV, and PQR. Interestingly, the SW*Y motif was also found in NM23. We are the first to implicate NM23 in IHHNV infection and postulate that it may bind to the CP using the SW*Y motif, although this remains to be confirmed.

PmRab7 is a VP28-binding protein involved in white spot syndrome virus infection in shrimp

Our aim was to isolate and characterize white spot syndrome virus (WSSV)-binding proteins from shrimp. After a blot of shrimp hemocyte membrane proteins was overlaid with a recombinant WSSV envelope protein (rVP28), the reactive bands on the blot were detected using anti-VP28 antibody. Among three membrane-associated molecules identified by liquid chromatography-tandem mass spectrometry, there was a 25-kDa protein that bound to both rVP28 and WSSV. Since it had a primary structure with high homology to the small GTP-binding protein Rab7, we named it Penaeus monodon Rab7 (PmRab7). The full-length PmRab7 cDNA was obtained, and results from a glutathione S-transferase pull-down assay confirmed specific binding to rVP28. Reverse transcriptase PCR analysis revealed PmRab7 expression in many tissues, and real-time PCR analysis revealed that expression was constitutive. Binding of PmRab7 to rVP28 or WSSV occurred in a dose-dependent manner and was inhibited by anti-Rab7 antibody. In an in vivo neutralization assay, the number of dead shrimp after challenge with WSSV plus PmRab7 (15%) or WSSV plus anti-Rab7 antibody (5%) was significantly lower than after challenge with WSSV alone (95%). In contrast to the WSSV-injected group, shrimp injected with WSSV plus PmRab7 or WSSV plus anti-Rab7 showed no WSSV-type histopathology. We conclude that PmRab7 is involved in WSSV infection in shrimp. This is the first study to identify a shrimp protein that binds directly to a major viral envelope protein of WSSV.