Ubiquitin signalling in the NF-κB pathway

The transcription factor NF-κB (nuclear factor kappa enhancer binding protein) controls many processes, including immunity, inflammation and apoptosis. Ubiquitination regulates at least three steps in the NF-κB pathway: degradation of IκB (inhibitor of NF-κB), processing of NF-κB precursors, and activation of the IκB kinase (IKK). Recent studies have revealed several enzymes involved in the ubiquitination and deubiquitination of signalling proteins that mediate IKK activation through a degradation-independent mechanism.