Description: Interleukin-31 (IL-31) is a member of the gp130/IL-6 family of cytokines that is produced predominantly, but not exclusively, by activated Th2 cells. It binds to a heterodimeric receptor complex consisting of IL-31RA (GPL, GLM-R), a gp130-like molecule, and oncostatin M receptor (OSMR). This receptor complex is expressed constitutively on keratinocytes and epithelial cells and can be upregulated on monocytes by IFN gamma or LPS. IL-31 signaling activates the Jak/STAT signaling pathway, including STAT1, STAT3, and STAT5, as well as the PI3 kinase/AKT and MAP kinase pathways. Mouse IL-31 shares 31% amino acid identity with human IL-31 but it does not bind to the human IL-31 receptor.