A novel mechanism of nuclear factor-κB regulation by adenoviral protein 14·7K

Abstract

Viruses have evolved many different ways to evade immune attacks. The adenoviral E3 protein 14·7K effectively inhibits antiviral immunity and inflammation. However, the underlying mechanism for this effect is unclear. Here we show that 14·7K is a potent inhibitor of nuclear factor (NF)-κB transcriptional activity following Toll-like receptor (TLR) or tumour necrosis factor (TNF) receptor signalling. The inhibition of the NF-κB activity occurs downstream of IκBα degradation and NF-κB translocation into the nucleus. Analysis of NF-κB DNA binding reveals that 14·7K specifically inhibits p50 homodimer DNA binding and that this inhibition is mediated through the interaction of 14·7K with p50. We propose that 14·7K inhibits NF-κB activity through directly blocking p50 binding to DNA and that this is the basis for its anti-inflammatory properties. Our data also indicate a role for p50 homodimer-dependent transcription in inflammation. © 2005 Blackwell Publishing Ltd.