The Pivotal Role of TBK1 in Inflammatory Responses Mediated by Macrophages

Table 1

TBK1, IKK family, and their characteristics.

Subtype	Domains	Phosphorylation site	Sequence identity (%)		Function	Reference
			IKK𝛼	IKK𝜀
Canonical; IKKs
IKK𝛼	KD, LZ, HLH, NBD	S176/180	100	27	Osteoclast differentiation; skin tumor suppressor; T-cell receptor signaling pathway; virus response; Toll-like receptor signaling pathway	[26–29]
IKK𝛽	KD, ULD, LZ, HLH, NBD	S177/181	52	24	Mediates chemoresistance for cell survival and death; regulates hepatic fibrosis	[30, 31]
IKK𝛾	CC1, CC2, LZ, ZF	S376	None; reported	None; reported	Regulates IκB kinase (IKK) complex, involved in inflammation, immunity, cell survival	[32, 33]
Noncanonical; IKKs
IKK𝜀	KD, ULD, LZ, HLH	S172	27	100	Regulates type I and type II interferon responses	[34]
TBK1	KD, ULD, LZ, HLH	S172	27	64	Regulates type I and type II interferon responses, mediates NF-𝜅B signaling, liver degeneration, cancer, hepatitis, colitis, and rheumatoid arthritis	[20, 22, 25, 28, 35, 36]

KD: kinase domain; HLH: helix-loop-helix; ULD: ubiquitin-like domain; LZ: leucine zipper; CC1: first coiled coil; CC2: second coiled coil; ZF: zinc finger.