Biochemical network model for the IKK-IкB-NF-кB-A20 signaling module. Top panel: A schematic description of our comprehensive model for NF-кB signaling. The arrows indicate activation and the perpendicular lines denote inhibition. Bottom panel: the model consists of IKK (IкB kinase), IкB isoforms (IкBi, i = α, β, ϵ), and A20. NF-кBn and IкBin denote their nuclear components. Squares are for proteins; hexagons are for mRNA. Black arrows indicate either association or dissociation or degradation of proteins; red (blue) arrows denote mRNA (protein) synthesis.