Proteins that bind to IKKγ (NEMO) and down-regulate 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 component of the IKK complex. Following the exposure of cells to NF-κB-inducing stimuli, the IKK complex catalyzes the phosphorylation of inhibitor of κB (IκB) proteins, which is a critical step that leads to the activation of NF-κB via the canonical pathway. The exact functions of IKKγ as part of the IKK complex have not been fully elucidated. A number of proteins have been identified as directly interacting with IKKγ and modulating the activity of the IKK complex. This mini review covers eight proteins that have been reported to bind to IKKγ and lead to the suppression of the activities of the IKK complex and hence result in the down-regulation of the activation of NF-κB. The reported mechanisms by which these interactions suppress the activation of the IKK complex include the deubiquitination of IKKγ and competition with upstream activators for binding to IKKγ.