IκBα

IκBα (Inhibitor of nuclear factor kappa-B alpha) is a protein that in humans is encoded by the NFKBIA gene. IκBα is a member of a family of cellular proteins that function to inhibit the NF-κB transcription factor. IκBα inhibits NF-κB by masking the nuclear localization signals (NLS) of NF-κB proteins and keeping them sequestered in an inactive state in the cytoplasm.

Function

IκBα is part of the NF-κB inhibitory complex, which inhibits NF-κB by trapping it in the cytoplasm. Upon activation, IκBα is phosphorylated by IκB kinase (IKK), ubiquitinated by a ubiquitin ligase, and then degraded by the proteasome, which allows NF-κB to enter the nucleus and activate the transcription of its target genes.

Clinical significance

Mutations in the NFKBIA gene are associated with various diseases, including Hodgkin's lymphoma, non-Hodgkin lymphoma, multiple myeloma, and colorectal cancer. In addition, the NFKBIA gene is often deleted in glioblastoma and mutations have been found in melanoma cells.

See also

• NF-κB
• IκB kinase
• Proteasome
• Ubiquitin ligase

External links

• NFKBIA at the National Center for Biotechnology Information

IκBα Resources
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