Anti-Human IKK Complex-Associated Protein (IKAP)

IKAP was initially identified as a scaffold protein of the IκB kinase complex that could bind to IKKα, IKKβ, NF-κB, and the NF-κB-inducing kinase (NIK), although later evidence has cast doubt on this. More recent reports show that mutations in IKAP such as a frameshift leading to a truncated protein or a missense mutation that leads to defective phosphorylation are responsible for the autosomal recessive genetic disease familial dysautonomia (FD). Reports indicating that it forms part of the RNA polymerase II transcription elongation complex suggest that this disease may be due to compromised transcription elongation. More recently, it was shown that IKAP associates with c-Jun N-terminal kinase (JNK) and could specifically enhance JNK activation induced by the upstream JNK activators MEKK1 and ASK1, indicating another possible cause for FD. At least two isoforms of IKAP are known two exist.