HSV-1 ICP27 suppresses NF-kappaB activity by stabilizing IkappaBalpha.

Nuclear factor kappaB (NF-kappaB) is associated with the transcriptional activation of genes encoding chemokines, adhesion molecules, cytokines, and anti-apoptotic proteins, which are key components in immune responses and viral infection. Many viruses modulate NF-kappaB through numerous viral gene products to allow productive infections and immune escape. Here we report that herpes simplex virus-1 infected cell protein 27 (HSV-1 ICP27), an immediate early protein of HSV-1, represses NF-kappaB activity through binding to inhibitor of kappaB (IkappaBalpha), blocking phosphorylation and ubiquitination of IkappaBalpha, and stabilizing IkappaBalpha. These data may explain how NF-kappaB activity is regulated by ICP27 to escape immune responses during the very early period of HSV-1 infection.