Herpes Simplex Virus 1 Induces Phosphorylation and Reorganization of Lamin A/C through the γ 1 34.5 Protein That Facilitates Nuclear Egress

Abstract

ABSTRACT Herpes simplex virus 1 (HSV-1) remodels nuclear membranes during virus egress. Although the UL31 and UL34 proteins control nucleocapsid transit in infected cells, the molecular interactions required for their function are unclear. Here we report that the γ 1 34.5 gene product of HSV-1 facilitates nucleocapsid release to the cytoplasm through bridging the UL31/UL34 complex, cellular p32, and protein kinase C. Unlike wild-type virus, an HSV mutant devoid of γ 1 34.5 or its amino terminus is crippled for viral growth and release. This is attributable to a defect in virus nuclear egress. In infected cells, wild-type virus recruits protein kinase C to the nuclear membrane and triggers its activation, whereas the γ 1 34.5 mutants fail to exert such an effect. Accordingly, the γ 1 34.5 mutants are unable to induce phosphorylation and reorganization of lamin A/C. When expressed in host cells γ 1 34.5 targets p32 and protein kinase C. Meanwhile, it communicates with the UL31/UL34 complex through UL31. Deletion of the amino terminus from γ 1 34.5 disrupts its activity. These results suggest that disintegration of the nuclear lamina mediated by γ 1 34.5 promotes HSV replication. IMPORTANCE HSV nuclear egress is a key step that determines the outcome of viral infection. While the nuclear egress complex mediates capsid transit across the nuclear membrane, the regulatory components are not clearly defined in virus-infected cells. We report that the γ 1 34.5 gene product, a virulence factor of HSV-1, facilitates nuclear egress cooperatively with cellular p32, protein kinase C, and the nuclear egress complex. This work highlights a viral mechanism that may contribute to the pathogenesis of HSV infection.