Claim: The NFKB complex is inhibited by I-kappa-B proteins, phosphorylation (biochemical process that involves the addition of phosphate to an organic compound) of the serine residues of which by kinases marks them for destruction via the ubiquitination pathway, thereby allowing activation of the NF-kappa-B complex.
Evidence: The NFKB complex is inhibited by I-kappa-B proteins (NFKBIA, MIM 164008, or NFKBIB), which inactivate NF-kappa-B by trapping it in the cytoplasm. Phosphorylation of serine residues on the I-kappa-B proteins by kinases (IKBKA, MIM 600664 or IKBKB, MIM 603258) marks them for destruction via the ubiquitination pathway, thereby allowing activation of the NF-kappa-B complex. In chemistry, phosphorylation (a phosphate group is added to a molecule) of a molecule is the attachment of a phosphoryl group.