Alternative nuclear functions for NF-κB family members

The NF-kappa B signalling pathway regulates many different biological processes from the cellular level to the whole organism. The majority of these functions are completely dependent on the activation of the cytoplasmic IKK kinase complex that leads to I kappa B degradation and results in the nuclear translocation of specific NF-kappa B dimers, which, in general, act as transcription factors. Although this is a well-established mechanism of action, several publications have now demonstrated that some members of this pathway display additional functions in the nucleus as regulators of NF-kappa B-dependent and independent gene expression. In this review, we compiled and put in context most of the data concerning specific nuclear roles for IKK and I kappa B proteins.