Multifunctional cytokine mainly produced by T-cells that plays a regulatory role in immune response, tissue homeostasis, host defense, and oncogenesis (, ). Possesses antiviral functions and induces the type I interferon response during influenza infection . Signals through two receptor complexes IL20RA/IL20RB or IL20RB/IL22RA1 (, ). In turn, stimulates the JAK1-STAT3 and MAPK pathways and promotes the secretion of pro-inflammatory mediators including IL8 and MMP1 . Intracellularly, maintains endoplasmic reticulum homeostasis by restricting the eIF2alpha-CHOP pathway-mediated stress signal (By similarity). In addition, acts as a quality control mechanism for the ubiquitin proteasome system by alerting the cell to proteasome dysfunction through activation of PKR/EIF2AK2 (By similarity).
Subcellular locations: Secreted
Up-regulated in melanoma cells induced to terminally differentiate.