IKB alpha peptide

Three major forms of IkB-like molecules have been identified and each is characterized by multiple copies of ankyrin repeats. IkB-alpha and IkB-beta appear to be the major regulatory forms of IkB in most cells. These proteins interact with p65 or c-Rel containing forms of NFkB and block nuclear import by masking the nuclear localization sequences of NFkB. The activation of NFkB involves the inducible phosphorylation and subsequent degradation of IkB. Immunoblotting easily detects the hyper-phosphorylated forms of IkB-alpha, but not phosphorylated IkB-beta. Interestingly, IkB-alpha and IkB-beta mediate different NFkB responses. IkB-alpha appears to control more transient activation of NFkB in response to an inducer, while IkB-beta controls a persistent response. Bcl-3 interacts with p5 and p52 containing forms of NFkB, but rather than being an inhibitor it appears to function to stimulate transcription. The degradation of IkB is confirmed by immunoblotting.