Components of the IKK Complex The IκB kinase (IKK) complex consists of two catalytic subunits IKKα (IKK1) and IKKβ (IKK2), as well as a non-catalytic accessory protein IKKγ. IKKγ is also known as NF-κB essential modulator (NEMO). IKKα and IKKβ have high sequence homology and hence, are structurally similar. Both of those subunits possess phosphorylating