IL-33: A Cytokine that Acts as an Alarm Signal in Innate Immune Responses
Download as PDF
Gao Jianhua, Cao Hua, Wang Chuan, Fang Yihu
Interleukin-33 (IL-33) is a member of the interleukin-1 family (IL-1F), which is constitutively expressed in normal tissues and rapidly released under cell injury or stress, acting as a alarm signal.IL-33 binds to the IL-1 family orphan receptor T1/ST2, this complex and the IL-1 receptor accessory protein IL-1RAcP act as co-receptors to mediate signaling through the NF-κB and MAPK pathways, and plays an important role in the innate immunity. IL-33 is a bifunctional protein that acts as a pro-inflammatory cytokine and a cellular nuclear factor with transcriptional regulatory properties. The IL-33 gene is located on the short arm 9p24.1 of chromosome 9, and contains eight exons, which are more than 42 kb in length and can produce two transcripts IL-33a and IL-33b mRNA, but they encode the same protein. The propeptide product contains two cleavage sites, which can be regulated by enzymatic hydrolysis. After apoptosis, caspase inactivates IL-33, whereas in the pathological (necrotic) cell death process, the IL-33 activity is greatly enhanced by inflammatory protease hydrolysis to rapidly activate the immune system to protect body tissues.
IL-33, cytokine, ST2 receptor, Immunological reaction