Missing Pieces in the NF-κB Puzzle

The regulation of the transcription factor NF-κB activity occurs at several levels including controlled cytoplasmic-nuclear shuttling and modulation of its transcriptional activity. A critical component in NF-κB regulation is the IκB kinase (IKK) complex. This review is focused on recent progress as well as unanswered questions regarding the regulation and function of NF-κB and IKK.