Fig. 1.

Production of IL-32 and its downstream signaling network. IL-32 is produced by a variety of cells (e.g., NK cells, T cells, monocytes, and epithelial cells), and its production can be stimulated by different cytokines (e.g., TNF-α, INF-α, IL-2, IL-18, and IL-1β). IL-32 synergizes with NOD1 and NOD2 and subsequently induces the production of IL-6 and IL-1β via a caspase-1–dependent signaling pathway. IL-32 can also activate NF-κB signaling through the IκB pathway (via NOD2-MDP or directly acting on IκB) and/or the p38-MAPK pathway