@Article{ecn.2012.0320,
AUTHOR = {Emma Lefrançais, Corinne Cayrol},
TITLE = {Mechanisms of IL-33 processing and secretion: differences and similarities between IL-1 family members*},
JOURNAL = {European Cytokine Network},
VOLUME = {23},
YEAR = {2012},
NUMBER = {4},
PAGES = {120--127},
URL = {http://www.techscience.com/ECN/v23n4/65685},
ISSN = {1952-4005},
ABSTRACT = {Interleukin-33 (IL-33) is the latest member of the IL-1 family that has become very attractive since
the discovery of its major target cells, the innate lymphoid cells type 2 (ILC2), involved in the initiation of the type 2
immune response (secretion of IL-5 and IL-13) during parasitic infection and allergic diseases such as asthma. IL-33
is a chromatin-associated protein as it possesses in its N-terminus, a chromatin-binding domain, and is constitutively
expressed in the nuclei of endothelial cells and in epithelial cells of tissues exposed to the environment. It is however,
essential for IL-33 to be extracellularly released to bind to its receptor ST2 through the C-terminus portion of the
protein in order to induce the inflammatory and type 2 responses. Like other IL-1 family members, IL-33 does
not possess any signal peptide and may be released through unconventional secretory mechanisms or following cell
damage and necrosis. It was initially believed that IL-33, like IL-1β and IL-18, requires processing by caspase-1 to
be released, and for biological activity. On the contrary, full length IL-33 is biologically active, and processing by
caspases results rather in IL-33 inactivation. Moreover, it has been recently shown that the bioactivity of IL-33 can
be increased by inflammatory proteases secreted in the microenvironment, similarly to IL-1α, IL-1β and IL-18. This
review will summarize recent progress on how IL-33 is released and processed compared with the other IL-1 family
members, and how the immune cells recruited to the site of injury can regulate the disease-associated function of
IL-33.},
DOI = {10.1684/ecn.2012.0320}
}