Figure 1

IL-13 signaling. Step 1, the binding of IL-13 to IL-13Rα1 leads to step 2, heterodimer formation with IL-4Rα1 and formation of the type 2 IL-4 receptor. Step 3 leads to Janus Kinase activation (JAK), followed by step 4, STAT6 phosphorylation, dimerization, and translocation to the nucleus. In step 5, Stat 6 heterodimers affect IL-13-dependent gene transcription. IL-13Rα2 is an IL-13 dependent gene. IL-13 can bind IL-13Rα2 that leads to sequestration of IL-13 or IL-13 signaling by TGF-β induction or AP-1 signaling. Mouse models suggest that suppressor of cytokine signaling (SOCS)1 is an IL-13 dependent gene that interacts with JAK2 to negatively regulate JAK2 association with IL-13Rα1 [14]. In a mouse model, SOCS5 targets IL-4Rα1 and impairs STAT6 signaling [15].