IkB-alphs (nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha) is one member of a family of cellular proteins that function to inhibit the NF-kB transcription factor. IkB-alpha inhibits NF-kB by masking the nuclear localization signals (NLS) of NF-kB proteins and keeping them sequestered in an inactive state in the cytoplasm. In addition, IkB-alpha blocks the ability of NF-kB transcription factors to bind to DNA, which is required for NF-kB's proper functioning. Mutations in the gene encoding IkB-alpha have linked to Hodgkin's lymphoma.