Phospho-RelB (Ser552) (Clone: A7) rabbit mAb

RelB contains the Rel homology Domain (RHD) shared by all members of the NF-kB family (1) . It is best known for its roles in lymphoid development, DC biology, and noncanonical signaling (2) . RelB is a major contributor to chromatin biology, frequently functioning as a dual transcription factor that silences sets of genes by generating silent facultative heterochromatin and activates euchromatin of others (3) . RelB is required to repress immediate-response proinflammatory genes during endotoxin tolerance (4) . The N-terminal leucine zipper motif of RelB, a motif unique among the NF-kB family, may associate with more diverse DNA sequences than other NF-kB members (5) . RelB binds to DNA but only after forming a heterodimer with NF-kB p50 or p52 (6) . Like all NF-kB members, RelB contains an approximately 300-residue region known as the RHD. This region supports many of the NF-kB essential functions, such as DNA binding, dimerization, and nuclear localization (7) . RelB, unlike other NF-kB members, has an N-terminal leucine zipper motif (1), a domain that can typically interact with many proteins (8) . p100, the C-terminus of NF-kB2 acts as a RelB inhibitor (9), where it sequesters RelB in the cytosol to repress its activity. RelB is phosphorylated rapidly at threonine 84 and serine 552, causing cleavage at the N-terminus and its degradation by the proteasome (10) . These phosphorylations are mediated by glycogen synthase kinase-3B, specific inhibition of which blocks phospho RelB phosphorylation and degradation (11) . This degradation does not occur when phospho RelB is phosphorylated at serine 368, allowing its association with and stabilization by p100 (12) .