Antibody detects endogenous levels of IKB epsilon only when phosphorylated at Serine 161. NFKB1 or NFKB2 is bound to REL, RELA, or RELB to form the NFKB complex. The NFKB complex is inhibited by I-kappa-B proteins (NFKBIA, MIM 164008 or NFKBIB, MIM 60449