IKK-α is part of the IκB kinase complex that plays an important role in regulating the NF-κB transcription factor. IKK-β is an enzyme that serves as a protein subunit of IκB kinase, which is a component of the cytokine-activated intracellular signaling pathway involved in triggering immune responses. IKK's activity causes activation of a transcription factor known as Nuclear Transcription factor kappa-B or NF-κB. Activated IKK-β phosphorylates a protein called the inhibitor of NF-κB, IκB (IκBα), which binds NF-κB to inhibit its function. IKK-α and IKK-β phosphorylate the IκB proteins, marking them for degradation via ubiquitination and allowing NF-κB transcription factors to go into the nucleus. Once activated, NF-κB transcription factors regulate genes that are implicated in many important cellular processes, including immune response, inflammation, cell death, and cell proliferation.