TBKBP1 is an adaptor protein belonging to the fibrillar collagen family, consisting of trimers of identical alpha 1 chains which are linked to each other by interchain disulfide bonds. It is essential for signal transduction during viral infection and plays a major role in the NF-kB pathway. TBKBP1 is thus required for efficient IRF (interferon regulatory factor) activation by Sendai virus. The protein binds TBK1 (TANK-binding kinase) and IKKi (inhibitor of nuclear factor B kinase, inducible) via a newly identified TBK1/IKKi-binding domain (TBD), which it shares with TANK and NAP1. Binding to kinases via TBD is essential for IRF3 (interferon regulatory factor 3) activation which controls the expression of antiviral genes during infection. The protein has a ubiquitous expression with highest levels in ovary, followed by testis and brain. Human TBKBP1 gene is mapped to chromosome 17q21.32.