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. 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; also stimulates its own expression and that of the prototypic cutaneous pro-inflammatory parameters TNF-alpha, S100A7/psoriasin and inducible NOS. May play a role in pro-inflammatory responses during particular neutrophilic airway inflammation: activates mitogen-activated protein kinases and NF-kappa B in primary lung fibroblasts, and stimulates the expression of IL-8 and CXCL3 and Th17 chemokine CCL20 in lung fibroblasts. May be involved in the innate immune response to fungal pathogens, such as Aspergillus fumigatus. Interacts with cargo receptor 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. Highly expressed in tissues containing epithelial cells: skin, lung, stomach and esophagus. Expressed in bronchial epithelial. In skin is expressed only in keratinocytes but not in fibroblasts, endothelial cells or melanocytes. Up-regulated in lesional psoriasis skin. Expressed in monocyte-derived dendritic cells and M1 macrophages. By TNF and by IFNG/IFN-gamma in keratinocytes. By Aspergillus fumigatus conidia in peripheral blood mnonocytes; involves CLEC7A and SYK. N-terminal truncation leads to a dramatic enhancement of its activity (>1000-fold) (PubMed:21965679). Proteolytically cleaved by cathepsin CTSG (PubMed:30804664). Belongs to the IL-1 family. Interleukin-1 entry