BD Phosflow™ Alexa Fluor® 488 Mouse anti-TBK1

NF-κB is a ubiquitously expressed transcription factor that regulates many cytokine and Ig genes.  It is involved in immune, inflammatory, viral, and acute phase responses.  In most cells, NF-κB is sequestered in an inactive cytoplasmic form via interactions with the inhibitory proteins IκBα, IκBβ, and IκBε.  Stimulation induces the release, activation, and nuclear translocation of NF-κB.  Release of NF-κB results from the phosphorylation and proteolytic degradation of the IκB proteins.  Two cytokine-inducible IκB kinases (IKKα and IKKβ) phosphorylate and target the IκB proteins for degradation via the ubiquitin pathway.  IKKγ/NEMO, a third member of the IKK complex, functions as a regulatory subunit and interacts directly with IKKβ.  TBK1 (TANK-binding kinase 1, also known as T2K or NAK), a protein of 729 amino acids, is another member of the IKK family of kinases regulating NF-κB downstream of the tumor necrosis factor and Toll-like receptor pathways.  TBK1 forms a complex with the adaptor proteins TANK (TRAF-associated NF-κB activator) and TRAF2 (TNF-receptor-associated factor 2), and this oligomer is required for activation and phosphorylation of TBK1 at serine 172.

The 637Ig11.2 monoclonal antibody recognizes human TBK1, regardless of phosphorylation status.  Our in-house testing is performed on a cell line that has been co-transfected with TBK1 and IRF-7 because we have been unable to detect endogenous TBK1 by western blotting of lysates from activated cell lines (HeLa activated with PMA and A431 activated with PDGF).  In the transfectants, the over-expression of TBK1 is necessary for phosphorylation of IRF-7, but the presence of IRF-7 does not affect TBK1 expression or phosphorylation.  We confirmed that mAb 637Ig11.2 does not cross-react with IRF-7 by western blot analysis using the purified antibody.