Protein-protein interactions involving IKKγ (NEMO) that promote the activation of NF-κB

Inhibitor of κB kinase (IKK) gamma (IKKγ), also referred to as nuclear factor κB (NF-κB) essential modulator (NEMO), is an important regulatory component of the IKK complex. The IKK complex is a signalosome that catalyzes the inducible phosphorylation of IκB proteins, which is a key step that leads to the activation of NF-κB. The exact functions of IKKγ (NEMO) as part of the IKK complex have not yet been fully elucidated. This mini-review covers 16 proteins that have been reported to bind to IKKγ and lead to the enhancement of the activities of the IKK complex, thus resulting in NF-κB activation. The major mechanisms by which these interactions are mediated involve the recognition of ubiquitinated upstream signaling components by IKKγ or the modification of IKKγ itself by ubiquitination. Additional mechanisms include the sumoylation or phosphorylation of IKKγ and the modification of the tertiary or quaternary structure of IKKγ.