NF-kappa-B inhibitor alpha (IκBα) (IκBα)

NF-kappa-B inhibitor alpha (IκBα) is a key regulatory protein that controls the activity of the NF-kappa-B transcription factor, a central mediator of inflammation and immune responses [1, 11]. In unstimulated cells, IκBα binds to NF-kappa-B dimers in the cytoplasm, masking their nuclear localization signals and preventing their translocation to the nucleus [1, 2]. Upon cellular stimulation by cytokines or pathogens, IκBα is phosphorylated by the IκB kinase (IKK) complex, which triggers its ubiquitination and subsequent degradation by the 26S proteasome [11, 15]. The loss of IκBα allows NF-kappa-B to enter the nucleus and initiate the transcription of various pro-survival and pro-inflammatory genes [11]. Dysregulation of this process, through mutations or excessive degradation of IκBα, is linked to chronic inflammatory diseases, autoimmune disorders, and various cancers, including Hodgkin's lymphoma and leukemia [1, 5, 8]. Therapeutic strategies involving this target focus on preventing IκBα degradation using proteasome inhibitors or IKK inhibitors to maintain NF-kappa-B in an inactive state [3, 4, 10]. Additionally, experimental therapies utilize "super-repressor" versions of IκBα that are resistant to degradation to achieve more targeted pathway inhibition [16, 17].

Other names

IKBAMAD-3NFKBINFKBIANuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alphaMajor histocompatibility complex enhancer-binding protein MAD3Ectodermal dysplasia anhidrotic with T-cell immunodeficiency autosomal dominant 2 (EDAID2)

Drugs typically modulate this target by preventing its phosphorylation via IKK inhibition or its degradation via proteasome inhibition, which stabilizes the IκBα/NF-kappa-B complex in the cytoplasm. This stabilization prevents nuclear translocation of NF-kappa-B and subsequent transcription of pro-inflammatory and anti-apoptotic genes. Experimental approaches also include the direct delivery of degradation-resistant "super-repressor" variants of the protein.