Cytokine that binds to and signals through the IL1RL2/IL-36R receptor which in turn activates NF-kappa-B and MAPK signaling pathways in target cells linked to a pro-inflammatory response. Part of the IL-36 signaling system that is thought to be present in epithelial barriers and to take part in local inflammatory response; similar to the IL-1 system with which it shares the coreceptor IL1RAP. Seems to be involved in skin inflammatory response by acting on keratinocytes, dendritic cells and indirectly on T-cells to drive tissue infiltration, cell maturation and cell proliferation. In cultured keratinocytes induces the expression of macrophage, T-cell, and neutrophil chemokines, such as CCL3, CCL4, CCL5, CCL2, CCL17, CCL22, CL20, CCL5, CCL2, CCL17, CCL22, CXCL8, CCL20 and CXCL1, and the production of pro-inflammatory cytokines such as TNF-alpha, IL-8 and IL-6. In cultured monocytes up-regulates expression of IL-1A, IL-1B and IL-6. In myeloid dendritic cells involved in cell maturation by up-regulating surface expression of CD83, CD86 and HLA-DR. In monocyte-derived dendritic cells facilitates dendritic cell maturation and drives T-cell proliferation. May play a role in pro-inflammatory effects in the lung. Interacts with TMED10; the interaction mediates the translocation from the cytoplasm into the ERGIC (endoplasmic reticulum-Golgi intermediate compartment) and thereby secretion. The secretion is dependent on protein unfolding and facilitated by the cargo receptor TMED10; it results in protein translocation from the cytoplasm into the ERGIC (endoplasmic reticulum-Golgi intermediate compartment) followed by vesicle entry and secretion. Expressed in immune system and fetal brain, but not in other tissues tested or in multiple hematopoietic cell lines. Predominantly expressed in skin keratinocytes but not in fibroblasts, endothelial cells or melanocytes. Increased in lesional psoriasis skin. By Il-1 and TNF-alpha. N-terminal truncation leads to a dramatic enhancement of its activity (>1000-fold). Initial experiments using non-processed full-length protein found in vitro activity only in the ug range. Belongs to the IL-1 family. Interleukin-1 entry