Voltage Dependent Anion Channel Is Redistributed during Japanese Encephalitis Virus Infection of Insect Cells

Abstract

Despite the availability of an effective vaccine, Japanese encephalitis remains a significant cause of morbidity and mortality in many parts of Asia. Japanese encephalitis is caused by the Japanese encephalitis virus (JEV), a mosquito transmitted flavivirus. Many of the details of the virus replication cycle in mosquito cells remain unknown. This study sought to determine whether GRP78, a well-characterized flavivirus E protein interacting protein, interacted with JEV E protein in insect cells, and whether this interaction was mediated at the cell surface. GRP78 was shown to interact with JEV E protein by coimmunoprecipitation, and was additionally shown to interact with voltage dependent anion protein (VDAC) through the same methodology. Antibody inhibition experiments showed that neither GRP78 nor VDAC played a role in JEV internalization to insect cells. Interestingly, VDAC was shown to be significantly relocalized in response to JEV infection, and significant levels of colocalization between VDAC and GRP78 and VDAC and ribosomal L28 protein were seen in JEV infected but not uninfected cells. This is the first report of relocalization of VDAC in response to JEV infection and suggests that this may be a part of the JEV replication strategy in insect cells.

Involvement of voltage-dependent anion channel (VDAC) in dengue infection

“…DENV replication is believed to occur in specific replication vesicles probably generated through re-organization of the ER membranes51. Consistent with our earlier study27 DENV infection resulted in increased colocalization between GRP78 and VDAC, and increased colocalization between VDAC and a ribosome marker (ribosomal protein L28). These results are consistent with mitochondria being bought nearer to the ER/replication sites, rather than GRP78 relocalizing towards VDAC.…”

“…This, coupled with our previous study showing an interaction between JEV E protein and GRP78 in insect cells27, suggests that this interaction might be a common interaction in flavivirus infections. In particular these studies raise the question of whether the specific binding of DENV E protein to GRP78 triggers the UPR or whether the interaction is secondary to the mass of unfolded proteins entering the ER during DENV infection.…”

“…In a previous study we showed that VDAC was relocalized in response to JEV infection of insect cells27. In this study we have shown that VDAC is relocalized in DENV infection in mammalian cells, and this occurred with both the DENV 2 and DENV 4 isolates investigated.…”

“…In a recent study we observed an interaction between Japanese encephalitis virus (JEV) E protein and GRP78 as well as the interaction between GRP78 and voltage dependent anion channel (VDAC) in insect (C6/36) cells27. Neither GRP78 nor VDAC were shown to play a role in JEV internalization to insect cells, and while there was no direct interaction between JEV E protein and VDAC, we observed significant relocalization of VDAC during JEV infection27.…”

“…Neither GRP78 nor VDAC were shown to play a role in JEV internalization to insect cells, and while there was no direct interaction between JEV E protein and VDAC, we observed significant relocalization of VDAC during JEV infection27. This study sought to determine whether VDAC played a role in DENV infection of mammalian cells, which might imply a broadly conserved mechanism in flavivirus infections.…”