Fig. 1.

The IL-33/ST2 signaling pathway in mast cells. IL-33 is primarily expressed by different types of structural cells. Damage to these cells by external stimuli results in cell injury followed by release of IL-33. IL-33 can be neutralized by binding to soluble ST2 (sST2) or recognized by membrane bound ST2 receptor, which subsequently leads to activation of MyD88 dependent signaling pathways and the release of mast cell mediators that play important roles in the progression of allergic diseases