TNF α /NF- κ B Signaling Pathway. The TNFα/NF-κ B signaling pathway. (a) The network. (b) The Tree of Complexes representation. The flow of action is visually represented by background colors: green for activators (IKKs) and yellow for inhibitors (Iκ Bs, and p100). The NIK kinase is in the first functional group (A), together with all three members of the IKK complex and p100. Functional group B includes, in addition to p100, the IKKs and two inhibitors Iκ Bα and Iκ Bβ. This group is the beginning of interaction between IKKs and Iκ Bs. Functional group C loses some of the IKKs, continues to show Iκ B and begins to show interaction between Iκ Bs and NF-κ B factors. Finally, in group E we see the entrance of NIK-independent Col-Tpl2 kinase.