Cellular p32 Recruits Cytomegalovirus Kinase pUL97 to Redistribute the Nuclear Lamina

Manfred Marschall,Andrea Marzi,Patricia Aus Dem Siepen,Ramona Jochmann,Martina Kalmer,Sabrina Auerochs,Peter Lischka,Martina Leis,Thomas Stamminger

doi:10.1074/jbc.m502672200

Manfred Marschall, Andrea Marzi + Show 7 more

Open Access

https://doi.org/10.1074/jbc.m502672200

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Abstract

Replication of human cytomegalovirus is limited at the level of nucleocytoplasmic transport of viral capsids, a process that requires the disassembly of the nuclear lamina. Deletion of the protein kinase gene UL97 from the viral genome showed that the activity of pUL97 plays an important role for viral capsid egress. Here, we report that p32, a novel cellular interactor of the viral kinase pUL97, promotes the accumulation of pUL97 at the nuclear membrane by recruiting the p32-pUL97 complex to the lamin B receptor. Transfection of active pUL97, but not a catalytically inactive mutant, induced a redistribution of lamina components as demonstrated for recombinant lamin B receptor-green fluorescent protein and endogenous lamins A and C. Consistent with this, p32 itself and lamins were phosphorylated by pUL97. Importantly, overexpression of p32 in human cytomegalovirus-infected cells resulted in increased efficiency of viral replication and release of viral particles. Thus, it is highly suggestive that the cellular protein p32 recruits pUL97 to induce a dissolution of the nuclear lamina thereby facilitating the nuclear export of viral capsids.

Highlights

Concerning the replication of human cytomegalovirus (HCMV), which is a major human pathogenic herpesvirus, little information has been published on destabilization of the nuclear lamina
Because the nuclear lamina is a natural barrier for nucleocytoplasmic transition independent of the nuclear pore complex, we investigated the morphology of the nuclear lamina in phosphorylating activity of the UL97-encoded viral kinase (pUL97)-expressing cells
A link between pUL97 and alterations of the nuclear lamina could be demonstrated with HCMV (AD169)-infected cells, whereas this effect was absent from cells infected with UL97-deleted HCMV (BAC213; Fig. 1D)

Summary

Introduction

Concerning the replication of human cytomegalovirus (HCMV), which is a major human pathogenic herpesvirus, little information has been published on destabilization of the nuclear lamina. In the presence of active pUL97 kinase (but not the inactive mutant) lamin A/C disappeared from the nuclear rim and was redistributed in a fashion similar to that observed for LBR-GFP (Fig. 1B, b).

Results

Conclusion