Ubiquitin signalling in the NF-κB pathway

The transcription factor NF-kappa B (nuclear factor kappa enhancer binding protein) controls many processes, including immunity, inflammation and apoptosis. Ubiquitination regulates at least three steps in the NF-kappa B pathway: degradation of I kappa B (inhibitor of NF-kappa B), processing of NF-kappa B precursors, and activation of the I kappa B 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.