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 proinflammatory parameters TNF-alpha, S100A7/psoriasin and inducible NOS. May play a role in proinflammatory 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. {ECO:0000269|PubMed:11466363, ECO:0000269|PubMed:20870894, ECO:0000269|PubMed:21965679, ECO:0000269|PubMed:23095752, ECO:0000269|PubMed:23147407, ECO:0000269|PubMed:24829417}.