Human IL33

IL-33, also known as NF-HEV and DVS 27, is a 30 kDa proinflammatory protein that may also regulate gene transcription. IL 33 was identified based on sequence and structural homology with IL 1 family cytokines. IL 33 is constitutively expressed in smooth muscle and airway epithelia. It is up-regulated in arterial smooth muscle, dermal fibroblasts, and keratinocytes following IL 1 alpha or IL 1 beta stimulation. Similar to IL 1, IL 33 can be cleaved in vitro by caspase 1, generating an N terminal fragment that is slightly shorter than the C terminal fragment. A ternary signaling complex is formed by the subsequent association of IL 33 and ST2L with IL 1R AcP. Human IL 33 shares less than 20% aa sequence identity with other IL 1 family proteins (1-5).