NF-kB and virus infection: who controls whom.

Among the different definitions of viruses, `pirates ofthe cell' is one of the most picturesque, but also one ofthe most appropriate. Viruses have been known for along time to utilize a variety of strategies to penetratecells and, once inside, to take over the host nucleicacid and protein synthesis machinery to build up theirown components and produce large amounts of viralprogeny. As their genomes carry a minimal amount ofinformation, encoding only a few structural and regulatoryproteins, viruses are largely dependent on theirhosts for survival; however, despite their apparentsimplicity, viruses have evolved different replicativestrategies that are regulated in a sophisticated manner.During the last years, the study of the elaboraterelationship between viruses and their hosts has led tothe understanding of how viral pathogens not only areable to alter the host metabolism via their signalingproteins, but are also able to hijack cellular signalingpathways and transcription factors, and control themto their own advantage. In particular, the nuclearfactor-kB (NF-kB) pathway appears to be an attractivetarget for common human viral pathogens. Thisreview summarizes what is known about the controlof NF-kB by viruses, and discusses the possible outcomeof NF-kB activation during viral infection,which may benefit either the host or the pathogen.